Warm-up3.1 Constructions and 4.1 Triangle Sum Theorem

1) Name the corresponding angle(s) to .2) Name two pairs of alternate exterior angles.3) Name all angles congruent to LMD.4) What is the relationship between ?

EHA

BHMAHM and

Student of the day!Block 4

Student of the day!Block 5

Student of the day!Block 6

Start of ConstructionsConstructions involve using a compass and straightedge. • No measuring with rulers or protractor.

Copying a segment. 1) Put one end of the compass one end of the segment .2) Stretch the compass to the other end and draw an arc.3) With a straightedge draw a long straight line.4) Using the same compass setting from 2) draw the arc withthe compass end on the end of the line you just drew.

When copying segments and angles always start with a ray.

Copying an angle

1) Draw an arc through the original angle.

2) Use your straightedge to draw a line.

3) Using the same compass setting from 1) draw an arcthrough the line in 2)

4) Use the arc drawn across the original angle from 1) tomeasure across the angle using the compass. (Draw a small arcto mark the intersection at the top. Keep that compass setting.

5) On the line with arc drawn for 3) use the intersection at the bottom

to draw the intersection above with the compass.

6) Connect the end of the line segment with the intersection from 5).

Copying an obtuse angleusing linear pairs

4.1 Triangle Sum Theorem

Prove: Triangle Sum Conjecture Given: Line EB is parallel to Segment ACTwo Column Proof:

4.1 Continued…

C-17 Triangle Sum ConjectureThe sum of measures of the angles in every triangle is ______.

H.W. Assignment

3.1 pg 147 #1-4To get credit on the 3.1 homework, you must showcompass marks. If you do not leave the arcs, youwill not get credit.

4.1 pg 203 #2-9